About IDOR

Enrolling as an Automated/Bulk Filer of Business Income Tax (BIT) Returns

Participation in the Illinois Electronic Filing Program for Business Income Tax returns is available to software developers, transmitters, Electronic Return Originators (EROs), and taxpayers. To use this method of filing, you can write your own software or buy software from an accepted electronic filer (third party).

If you wish to create your own software for filing or create software to sell, please refer to the BTR-36, Implementation Guide for Business Income Tax Federal/State Electronic Filing Program. To enroll, complete Form IL-8633-B, Business Electronic Filing Enrollment. Once we have received your enrollment form, you may begin testing.

For questions regarding this program, please contact the Electronic Commerce Division at 1-866-440-8680.

Note: Some taxpayers are required to pay their tax electronically using Electronic Funds Transfer.